'Put that down!' Will hissed. 'What are you doing here?'

Nico was dumbstruck. Will and two other campers were crouched in the grass, binoculars around their necks and daggers at their side. They wore black jeans and T-shirts, with black grease paint on their faces like commandos.

'Me?' Nico asked. 'What are you doing? Getting yourselves killed?'

Will scowled. 'Hey, we're scouting the enemy. We took precautions.'

'You dressed in black,' Nico noted, 'with the sun coming up. You painted your face but didn't cover that mop of blond hair. You might as well be waving a yellow flag.'

Will's ears reddened. 'Lou Ellen wrapped some Mist around us, too.'

'Hi.' The girl next to him wriggled her fingers. She looked a little flustered. 'You're Nico, right? I've heard a lot about you. And this is Cecil from Hermes cabin.'

Nico knelt next to them. 'Did Coach Hedge make it to camp?'

Lou Ellen giggled nervously. 'Did he ever.'

Will elbowed her. 'Yeah. Hedge is fine. He made it just in time for the baby's birth.'

'The baby!' Nico grinned, which hurt his face muscles. He wasn't used to making that expression. 'Mellie and the kid are all right?'

'Fine. A very cute little satyr boy.' Will shuddered. 'But I delivered it. Have you ever delivered a baby?'

'Um, no.'

'I had to get some fresh air. That's why I volunteered for this mission. Gods of Olympus, my hands are still shaking. See?'

He took Nico's hand, which sent an electric current down Nico's spine. He quickly withdrew. 'Whatever,' he snapped. 'We don't have time for chitchat. The Romans are attacking at dawn and I've got to '

'We know,' Will said. 'But, if you're planning to shadow-travel to that command tent, forget it.'

Nico glared at him. 'Excuse me?'

He expected Will to flinch or look away. Most people did. But Will's blue eyes stayed fixed on his annoyingly determined. 'Coach Hedge told me all about your shadow-travel. You can't try that again.'

'I just did try it again, Solace. I'm fine.'

'No, you're not. I'm a healer. I could feel the darkness in your hand as soon as I touched it. Even if you made it to that tent, you'd be in no shape to fight. But you wouldn't make it. One more slip, and you won't come back. You are not shadow-travelling. Doctor's orders.'

'The camp is about to be destroyed '

'And we'll stop the Romans,' Will said. 'But we'll do it our way. Lou Ellen will control the Mist. We'll sneak around, do as much damage as we can to those onagers. But no shadow-travel.'

'But '

'No.'

Lou Ellen's and Cecil's heads swivelled back and forth like they were watching a really intense tennis match.

Nico sighed in exasperation. He hated working with other people. They were always cramping his style, making him uncomfortable. And Will Solace ... Nico revised his impression of the son of Apollo. He'd always thought of Will as easygoing and laid back. Apparently he could also be stubborn and aggravating.

Nico gazed down at Camp Half-Blood, where the rest of the Greeks were preparing for war. Past the troops and ballistae, the canoe lake glittered pink in the first light of dawn. Nico remembered the first time he'd arrived at Camp Half-Blood, crash-landing in Apollo's sun car, which had been converted into a fiery school bus.

He remembered Apollo, smiling and tanned and completely cool in his shades.

Thalia had said, He's hot.

He's the sun god, Percy replied.

That's not what I meant.

Why was Nico thinking about that now? The random memory irritated him, made him feel jittery.

He had arrived at Camp Half-Blood thanks to Apollo. Now, on what would likely be his last day at camp, he was stuck with a son of Apollo.

'Whatever,' Nico said. 'But we have to hurry. And you'll follow my lead.'

'Fine,' Will said. 'Just don't ask me to deliver any more satyr babies and we'll get along great.'

XLVI.

Nico

THEY MADE IT TO THE FIRST ONAGER just as chaos broke loose in the legion.

On the far end of the line, cries went up from the Fifth Cohort. Legionnaires scattered and dropped their pila. A dozen centaurs barrelled through the ranks, yelling and waving their clubs, followed by a horde of two-headed men banging on trash-can lids.

'What's going on down there?' Lou Ellen asked.

'That's my distraction,' Nico said. 'Come on.'

All the guards had clustered on the right side of the onager, trying to see what was going on down the ranks, which gave Nico and his comrades a clear shot to the left. They passed within a few feet of the nearest Roman, but the legionnaire didn't notice them. Lou Ellen's Mist magic seemed to be working.

They jumped the spiked trench and reached the machine.

'I brought some Greek fire,' Cecil whispered.

'No,' Nico said. 'If we make the damage too obvious, we'll never get to the other ones in time. Can you recalibrate the aim like, towards the other onagers' firing lines?'

Cecil grinned. 'Oh, I like the way you think. They sent me because I excel at messing things up.'

He went to work while Nico and the others stood guard.

Meanwhile the Fifth Cohort was brawling with the two-headed men. The Fourth Cohort moved in to help. The other three cohorts held their positions, but the officers were having trouble keeping order.

'All right,' Cecil announced. 'Let's move.'

They shuffled across the hillside towards the next onager.

This time the Mist didn't work so well. One of the onager guards yelled, 'Hey!'

'Got this.' Will sprinted off which was possibly the stupidest diversion Nico could imagine and six of the guards chased after him.

The other Romans advanced on Nico, but Lou Ellen appeared out of the Mist and yelled, 'Hey, catch!'

She lobbed a white ball the size of an apple. The Roman in the middle caught it instinctively. A twenty-foot sphere of powder exploded outwards. When the dust settled, all six Romans were squealing pink piglets.

'Nice work,' Nico said.

Lou Ellen blushed. 'Well, it's the only pig ball I have. So don't ask for an encore.'

'And, uh ' Cecil pointed 'somebody better help Will.'

Even in their armour, the Romans were starting to gain on Solace. Nico cursed and raced after them.

He didn't want to kill other demigods if he could avoid it. Fortunately, he didn't need to. He tripped the Roman in the back and the others turned. Nico jumped into the crowd, kicking groins, smacking faces with the flat of his blade, bashing helmets with his pommel. In ten seconds, the Romans all lay groaning and dazed on the ground.

Will punched his shoulder. 'Thanks for the assist. Six at once isn't bad.'

'Not bad?' Nico glared at him. 'Next time I'll just let them run you down, Solace.'

'Ah, they'd never catch me.'

Cecil waved at them from the onager, signalling that his job was done.

They all moved towards the third siege machine.

In the legion ranks, everything was still in chaos, but the officers were starting to reassert control. The Fifth and Fourth Cohorts regrouped while the Second and Third acted as riot police, shoving centaurs and cynocephali and two-headed men back into their respective camps. The First Cohort stood closest to the onager a little too close for Nico's comfort but they seemed occupied by a couple of officers parading in front of them, shouting orders.

Nico hoped they could sneak up on the third siege machine. One more onager redirected and they might stand a chance.

Unfortunately, the guards spotted them from twenty yards away. One yelled, 'There!'

Lou Ellen cursed. 'They're expecting an attack now. The Mist doesn't work well against alert enemies. Do we run?'

'No,' Nico said. 'Let's give them what they expect.'

He spread his hands. In front of the Romans, the ground erupted. Five skeletons clawed out of the earth. Cecil and Lou Ellen charged in to help. Nico tried to follow, but he would've fallen on his face if Will hadn't caught him.

'You idiot.' Will put an arm around him. 'I told you no more of that Underworld magic.'

'I'm fine.'

'Shut up. You're not.' From his pocket, Will dug out a pack of gum.

Nico wanted to pull away. He hated physical contact. But Will was a lot stronger than he looked. Nico found himself leaning against him, relying on his support.

'Take this,' Will said.

'You want me to chew gum?'

'It's medicinal. Should keep you alive and alert for a few more hours.'

Nico shoved a stick of gum into his mouth. 'Tastes like tar and mud.'

'Stop complaining.'

'Hey.' Cecil limped over, looking like he'd pulled a muscle. 'You guys kind of missed the fight.'

Lou Ellen followed, grinning. Behind them, all the Roman guards were tangled in a weird assortment of ropes and bones.

'Thanks for the skeletons,' she said. 'Great trick.'

'Which he won't be doing again,' Will said.

Nico realized he was still leaning against Will. He pushed him away and stood on his own two feet. 'I'll do what I need to.'

Will rolled his eyes. 'Fine, Death Boy. If you want to get yourself killed '

'Do not call me Death Boy!'

Lou Ellen cleared her throat. 'Um, guys '

'DROP YOUR WEAPONS!'

Nico turned. The fight at the third onager had not gone unnoticed.

The entire First Cohort was advancing on them, spears levelled, shields locked. In front of them marched Octavian, purple robes over his armour, Imperial gold jewellery glittering on his neck and arms, and a crown of laurels on his head as if he'd already won the battle. Next to him was the legion's standard-bearer, Jacob, holding the golden eagle, and six huge cynocephali, their canine teeth bared, their swords glowing red.

'Well,' Octavian snarled, 'Graecus saboteurs.' He turned to his dog-headed warriors. 'Tear them apart.'

XLVII.